diff options
| -rw-r--r-- | fs/exec.c | 7 | ||||
| -rw-r--r-- | include/linux/tracehook.h | 121 | ||||
| -rw-r--r-- | kernel/fork.c | 41 |
3 files changed, 38 insertions, 131 deletions
diff --git a/fs/exec.c b/fs/exec.c index b37030d0a50b..8dca45b0dae8 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1224,7 +1224,12 @@ int check_unsafe_exec(struct linux_binprm *bprm) unsigned n_fs; int res = 0; - bprm->unsafe = tracehook_unsafe_exec(p); + if (p->ptrace) { + if (p->ptrace & PT_PTRACE_CAP) + bprm->unsafe |= LSM_UNSAFE_PTRACE_CAP; + else + bprm->unsafe |= LSM_UNSAFE_PTRACE; + } n_fs = 1; spin_lock(&p->fs->lock); diff --git a/include/linux/tracehook.h b/include/linux/tracehook.h index 8b06d4f2b814..bcc4ca762aee 100644 --- a/include/linux/tracehook.h +++ b/include/linux/tracehook.h @@ -130,27 +130,6 @@ static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int step) } /** - * tracehook_unsafe_exec - check for exec declared unsafe due to tracing - * @task: current task doing exec - * - * Return %LSM_UNSAFE_* bits applied to an exec because of tracing. - * - * @task->signal->cred_guard_mutex is held by the caller through the do_execve(). - */ -static inline int tracehook_unsafe_exec(struct task_struct *task) -{ - int unsafe = 0; - int ptrace = task->ptrace; - if (ptrace & PT_PTRACED) { - if (ptrace & PT_PTRACE_CAP) - unsafe |= LSM_UNSAFE_PTRACE_CAP; - else - unsafe |= LSM_UNSAFE_PTRACE; - } - return unsafe; -} - -/** * tracehook_tracer_task - return the task that is tracing the given task * @tsk: task to consider * @@ -169,106 +148,6 @@ static inline struct task_struct *tracehook_tracer_task(struct task_struct *tsk) } /** - * tracehook_prepare_clone - prepare for new child to be cloned - * @clone_flags: %CLONE_* flags from clone/fork/vfork system call - * - * This is called before a new user task is to be cloned. - * Its return value will be passed to tracehook_finish_clone(). - * - * Called with no locks held. - */ -static inline int tracehook_prepare_clone(unsigned clone_flags) -{ - int event = 0; - - if (clone_flags & CLONE_UNTRACED) - return 0; - - if (clone_flags & CLONE_VFORK) - event = PTRACE_EVENT_VFORK; - else if ((clone_flags & CSIGNAL) != SIGCHLD) - event = PTRACE_EVENT_CLONE; - else - event = PTRACE_EVENT_FORK; - - return ptrace_event_enabled(current, event) ? event : 0; -} - -/** - * tracehook_finish_clone - new child created and being attached - * @child: new child task - * @clone_flags: %CLONE_* flags from clone/fork/vfork system call - * @trace: return value from tracehook_prepare_clone() - * - * This is called immediately after adding @child to its parent's children list. - * The @trace value is that returned by tracehook_prepare_clone(). - * - * Called with current's siglock and write_lock_irq(&tasklist_lock) held. - */ -static inline void tracehook_finish_clone(struct task_struct *child, - unsigned long clone_flags, int trace) -{ - ptrace_init_task(child, (clone_flags & CLONE_PTRACE) || trace); -} - -/** - * tracehook_report_clone - in parent, new child is about to start running - * @regs: parent's user register state - * @clone_flags: flags from parent's system call - * @pid: new child's PID in the parent's namespace - * @child: new child task - * - * Called after a child is set up, but before it has been started running. - * This is not a good place to block, because the child has not started - * yet. Suspend the child here if desired, and then block in - * tracehook_report_clone_complete(). This must prevent the child from - * self-reaping if tracehook_report_clone_complete() uses the @child - * pointer; otherwise it might have died and been released by the time - * tracehook_report_clone_complete() is called. - * - * Called with no locks held, but the child cannot run until this returns. - */ -static inline void tracehook_report_clone(struct pt_regs *regs, - unsigned long clone_flags, - pid_t pid, struct task_struct *child) -{ - if (unlikely(child->ptrace)) { - /* - * It doesn't matter who attached/attaching to this - * task, the pending SIGSTOP is right in any case. - */ - sigaddset(&child->pending.signal, SIGSTOP); - set_tsk_thread_flag(child, TIF_SIGPENDING); - } -} - -/** - * tracehook_report_clone_complete - new child is running - * @trace: return value from tracehook_prepare_clone() - * @regs: parent's user register state - * @clone_flags: flags from parent's system call - * @pid: new child's PID in the parent's namespace - * @child: child task, already running - * - * This is called just after the child has started running. This is - * just before the clone/fork syscall returns, or blocks for vfork - * child completion if @clone_flags has the %CLONE_VFORK bit set. - * The @child pointer may be invalid if a self-reaping child died and - * tracehook_report_clone() took no action to prevent it from self-reaping. - * - * Called with no locks held. - */ -static inline void tracehook_report_clone_complete(int trace, - struct pt_regs *regs, - unsigned long clone_flags, - pid_t pid, - struct task_struct *child) -{ - if (unlikely(trace)) - ptrace_event(trace, pid); -} - -/** * tracehook_signal_handler - signal handler setup is complete * @sig: number of signal being delivered * @info: siginfo_t of signal being delivered diff --git a/kernel/fork.c b/kernel/fork.c index d4f0dff9d617..3c72a5b321a7 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1340,7 +1340,7 @@ static struct task_struct *copy_process(unsigned long clone_flags, } if (likely(p->pid)) { - tracehook_finish_clone(p, clone_flags, trace); + ptrace_init_task(p, (clone_flags & CLONE_PTRACE) || trace); if (thread_group_leader(p)) { if (is_child_reaper(pid)) @@ -1481,10 +1481,22 @@ long do_fork(unsigned long clone_flags, } /* - * When called from kernel_thread, don't do user tracing stuff. + * Determine whether and which event to report to ptracer. When + * called from kernel_thread or CLONE_UNTRACED is explicitly + * requested, no event is reported; otherwise, report if the event + * for the type of forking is enabled. */ - if (likely(user_mode(regs))) - trace = tracehook_prepare_clone(clone_flags); + if (likely(user_mode(regs)) && !(clone_flags & CLONE_UNTRACED)) { + if (clone_flags & CLONE_VFORK) + trace = PTRACE_EVENT_VFORK; + else if ((clone_flags & CSIGNAL) != SIGCHLD) + trace = PTRACE_EVENT_CLONE; + else + trace = PTRACE_EVENT_FORK; + + if (likely(!ptrace_event_enabled(current, trace))) + trace = 0; + } p = copy_process(clone_flags, stack_start, regs, stack_size, child_tidptr, NULL, trace); @@ -1508,20 +1520,31 @@ long do_fork(unsigned long clone_flags, } audit_finish_fork(p); - tracehook_report_clone(regs, clone_flags, nr, p); + + /* + * Child is ready but hasn't started running yet. Queue + * SIGSTOP if it's gonna be ptraced - it doesn't matter who + * attached/attaching to this task, the pending SIGSTOP is + * right in any case. + */ + if (unlikely(p->ptrace)) { + sigaddset(&p->pending.signal, SIGSTOP); + set_tsk_thread_flag(p, TIF_SIGPENDING); + } /* * We set PF_STARTING at creation in case tracing wants to * use this to distinguish a fully live task from one that - * hasn't gotten to tracehook_report_clone() yet. Now we - * clear it and set the child going. + * hasn't finished SIGSTOP raising yet. Now we clear it + * and set the child going. */ p->flags &= ~PF_STARTING; wake_up_new_task(p); - tracehook_report_clone_complete(trace, regs, - clone_flags, nr, p); + /* forking complete and child started to run, tell ptracer */ + if (unlikely(trace)) + ptrace_event(trace, nr); if (clone_flags & CLONE_VFORK) { freezer_do_not_count(); |